The most reasonably priced component used on the Civic 2005 (5) 4dr Ex (ka) Duct is the Screw,tapping,(po)4x.
Parts such as the Duct: Seal B(side Def), Duct L,joint (lh), Duct Assy,inst, Seal A are included in the Civic 2005 (5) 4dr Ex (ka) Duct parts fiche.
The sub assemblies and components that make up this Duct include this Duct Assy,inst, the most expensive part.